VIIth International Congress on the Biology of Fish, 19-22 July 2006, St. John's, Newfoundland and Labrador, Canada

Subject

stress response; Atlantic cod; larvae; fish nutrition

Abstract

Nutritional components of larval live-food enrichment diets, particularly highly unsaturated fatty acids (HUFAs), have been shown to influence larval post-stress survival and cortisol kinetics. Studies to date have found that altering the relative ratio of three specific HUFAs, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ArA), in larval diets has a significant effect on the stress response of several teleost species. Most commercial live-food enrichment products currently available differ greatly in their nutritional compositions and HUFA ratios. The objective of this study was to determine the effect of three different dietary regimes on growth and lipid composition of larval Atlantic cod during rearing as well as larval survival and whole-body cortisol kinetics following an acute air-exposure stress. The products used for the enrichment of both rotifers and Artemia included Advantage®, AlgaMac®, algae paste (Pavlova sp.) and INVE’s Selco® products. Larval growth, measured as standard length, over the rearing period revealed no significant differences between dietary treatments. Preliminary analysis of survival data suggests that larvae fed a live-food diet enriched with a combination of AlgaMac® products and Pavlova paste have higher post-stress survival than larvae fed livefood enriched with either Advantage® or Selco® products. The analysis of larval and live-food lipid samples as well as pre- and post-stress larval whole-body corticosteroid samples are on-going. Once completed, the survival and growth trends will be evaluated in the context of the dietary lipid profiles and the larval cortisol response

Language

English

Affiliation

NRC Institute for Marine Biosciences; National Research Council Canada